Suven Microdialysis Services In-Vivo Brain Microdialysis Studies in Rodents for Monitoring Changes in Neurotransmitters Acetylcholine Histamine and Metabolite GABA and Glutamate Monoamines (NE, DA, 5HT & Metabolites) Simultaneous Monitoring of Neurotransmitters and Unbound Test Compound Concentrations In-Vivo Spinal Microdialysis in Rodents for Monitoring Changes in Inflammatory Biomarkers and Neurotransmitters Responsible for Pain Mechanism of Action and PK/PD Studies CSF Pharmacokinetics Neurodegenerative models Contact: nvsrk@suven.com, jasti@suven.com 1 of 14
is a Bio-pharmaceutical Company in existence since 1989 based at Hyderabad, India. Suven Drug Discovery & Development Support Services (DDDSS) is providing research services to global Pharma and Biotech companies. Suven In-Vivo Microdialysis List / Type of Studies being offered Microdialysis team has expertise in conducting brain and spinal microdialysis studies to measure neuronal changes in freely moving animals. Using brain microdialysis, we evaluate the modulation of neurotransmitters (and/or test compound) in most of the brain areas of freely moving animals. Spinal microdialysis evaluates modulation of inflammatory biomarkers and neurotransmitters in spinal regions. Neurotransmitters and test compounds are quantified by specific and sensitive analytical techniques. Infrastructure Six Microdialysis Workstations Twelve Animals Can Undergo Dialysis Simultaneously Automated and Programmed Sample Collection under Refrigeration Over 24 hours Well Trained and Team of Scientists 2-3 Weeks Turnover Time for a Typical Study Preclinical Species Rat (Wistar/Sprague Dawley) Guinea pig (Dunkin Hartley) Mouse Neurotransmitters Acetylcholine Glutamate Gamma-amino butyric acid (GABA) Histamine Dopamine, Norepinephrine and Serotonin Monoamine Metabolites Contact: nvsrk@suven.com, jasti@suven.com 2 of 14
Study Designs Parallel Treatment Groups Cross-over Treatment Design Mechanism of Action Studies using various Antagonists/Blockers PharmacoKinetic, PharmacoDynamic (PK/PD) Studies in vivo, by simultaneous monitoring of neurotransmitters and drug concentrations Routes of administration Systemic (p.o., i.p., s.c., i.v. bolus and infusion) Prolonged infusion using osmotic infusion pumps Local application (retrodialysis) Intracerebroventricular (ICV) injection Typical experimental protocol Preparation of animals for study Acclimatization 4-5 days Stereotaxic surgery.5-.75 h Recovery 2-5 days Guide cannula implantation Experimental Day Stabilization 1-2 h Probe implantation ~ 16 h before Basal collection 1-2 h Modulation of neurotransmitters in dialysates and test compound levels in dialysates and/ plasma Based on the protocol Test compound administration Flow rate: 1. 2. µl/min Sample collection intervals: Microdialysates: 15-3 min. Blood sampling (through jugular vein) from same animal: 6 8 points during absorption, distribution and elimination phase (or) same animal will be used after wash out period for exposure in plasma, brain and CSF (based on neurotransmitter profile) Contact: nvsrk@suven.com, jasti@suven.com 3 of 14
Fractions collectors: Samples are collected at 4 C using programmed, refrigerated fraction collectors (up to 24 h post treatment). Histological Probe placement verification: At the end of the experiment, probe placement is verified in each brain. Representative probe placement tracks in mpfc (a) and ventral hippocampus (b) of rat respectively. (a) (b) Overview of Analytical Methods: Microdialysis samples: Acetylcholine : LC-MS/MS (API-4) Amino acids : Glutamate and GABA HPLC + Fluorescence Histamine : HPLC + Fluorescence Monoamines : LC-MS/MS (API-4 Q-Trap) Monoamine metabolites : HPLC-ECD (BASi Epsilon) Test compounds : LC-MS/MS (API-4 Q-Trap) Prostaglandin E2 : ELISA CSF samples: Monoamines (5-HT & 5-HIAA) : HPLC + ECD (BASi or ESA) Histamine and alpha methyl histamine : HPLC + Fluorescence Prostaglandin E2 : ELISA Interleukin-1β : ELISA Contact: nvsrk@suven.com, jasti@suven.com 4 of 14
Plasma and Brain tissue samples: Monoamines : HPLC + ECD (BASi or ESA) Test compound : LC-MS/MS (API-4 Q-Trap) Summary of Validation Experiments Acetylcholine i. Modulation of acetylcholine in ventral hippocampus by donepezil in male Wistar rats 3 *** ** Donepezil PO 2.5 mgkg (n=5) *** Vehicle 5ml/kg PO (n=8) Acetylcholine (% Change) 2 1 *** *** ** ** ** * *** * * * ** ** * ** Flow rate: 1.5 µl/min Sampling duration: 2 min -8-4 4 8 12 16 2 24 28 32 36 ii. Modulation of acetylcholine in ventral hippocampus by Olanzapine in male Wistar rats 4 Acetylcholine (% Change) 35 3 25 2 15 1 Mean - Olanzapine(n=7) Mean - Vehicle(n=8) containing.1 µmol neostigmine Flow rate: 2.4 µl/min Sampling duration: 15 min 5-6 -3 3 6 9 12 15 18 21 24 27 3 33 36 Contact: nvsrk@suven.com, jasti@suven.com 5 of 14
iii. Modulation of acetylcholine by Olanzapine in prefrontal cortex of Dunkin-Hartley guinea pigs 4 Olanzapine (n=7) Acetylcholine (% of mean basal value 3 2 1 Vehicle (n=7) containing.1 µmol neostigmine Flow rate: 1.5 µl/min Sampling duration: 2 min -8-4 4 8 12 16 2 24 Quantification of Acetylcholine Acetylcholine concentrations in microdialysate samples are quantified by using HPLC coupled with tandem mass spectrometry (LC-MS/MS) without any sample pretreatment. Quantitation range:.5-13.5 nm Typical chromatogram of acetylcholine Calibration curve Contact: nvsrk@suven.com, jasti@suven.com 6 of 14
Glutamate i. SB-27146: modulation of glutamate in frontal cortex of male Sprague-Dawley rats Flow rate: 1.25 µl/min Sampling duration: 15 min ii. Ketamine: modulation of glutamate in prefrontal cortex of male Sprague-Dawley rats 25 Vehicle * * Glutamate (% increase) 2 15 1 5 Ketamine 18 mg/kg, s.c. * Flow rate: 3. µl/min Sampling duration: 2 min -6-4 -2 2 4 6 8 1 12 14 16 18 2 Quantification Concentrations of glutamate in dialysates are determined by pre-column derivatization using HPLC-fluorescence method. 14 12 1 Glutamate LU 8 6 4 2.727 1835 5.565 Glutamate 2 Calibration curve -2.5 1. 1.5 2. 2.5 3. 3.5 4. 4.5 5. 5.5 6. Minutes Contact: nvsrk@suven.com, jasti@suven.com 7 of 14
Histamine Modulation of histamine by GSK-189254 in prefrontal cortex of male Sprague-Dawley rats 6 Histamine (% of mean basal value) 5 4 3 2 GSK-189254 1 mg/kg, s.c. (n=7) Vehicle (n=7) Flow rate: 1.5 µl/min Sampling duration: 2 min 1-8 -4 4 8 12 16 2 24 Quantification Concentrations of histamine in microdialysates are analyzed by HPLC and fluorometric detection after post-column derivatization with O-phtaldialdehyde (OPA) reagent, which is delivered by a secondary flow system. Autosampler HPLC pump valve Column Reagent pump Fluorescence detector Reaction coil Calibration curve Contact: nvsrk@suven.com, jasti@suven.com 8 of 14
1 Standard Biological sample 7 Histamine 5 mau 2. 1 2 3 4 5 Minutes Contact: nvsrk@suven.com, jasti@suven.com 9 of 14
Dopamine, Norepinephrine and Serotonin i. Modulation of monoamines by venlafaxine in prefrontal cortex of male Sprague-Dawley rats Flow rate: 1. µl/min Sampling duration: 3 min ii. Modulation of monoamines by atomoxetine in prefrontal cortex of male Wistar rats % of mean basal value 8 6 4 2 Dopamine (n=9) Norepinephrine (n=9) -9-6 -3 3 6 9 12 15 18 21 24 Contact: nvsrk@suven.com, jasti@suven.com 1 of 14
Quantification The catecholamine neurotransmitters dopamine, norepinephrine and serotonin were subjected for derivatization with dansyl chloride and following precursor-product ion pairs were monitored with m/z 853.1 17.1, m/z 869.2 17.1 and m/z 643.3-17.1 for the dansylated dopamine, norepinephrine and serotonin respectively. The analytes were quantified using triple quadrupole tandem mass spectrometer in positive ionisation mode using atmospheric pressure ionization source (Ref: Nirogi et al. 213 Journal of Chromatography B. 913-914, p. 41-47). The test samples were quantified against a calibration curve prepared for each of the neurotransmitter using artificial cerebrospinal fluid in the calibration range of Dopamine.66-14.835 nmol Norepinephrine.66-14.728 nmol Serotonin.66-14.689 nmol Dopamine Norepinephrine Contact: nvsrk@suven.com, jasti@suven.com 11 of 14
Serotonin Contact: nvsrk@suven.com, jasti@suven.com 12 of 14
Determination of unbound brain concentrations of test compounds in rats. i. Unbound concentration of escitalopram in prefrontal cortex Concentration (ng/ml) 25 2 15 1 5 Plasma concentrations Vs time profile Dialysate concentration Vs time profile 4 8 12 16 2 24 28 32 36 Flow rate: 1. µl/min Sampling duration: 2 min Test compound: Escitalopram 2.5 mg/kg, i.v. ii. Unbound brain concentration of quetiapine in striatum Quetiapine (ng/ml) 1.2 1.8.6.4 Mean - Quetiapine (n=3) Flow rate: 1.2 µl/min Sampling duration: 2 min Test compound: Quetiapine 3. mg/kg, s.c..2-2 2 4 6 8 1 12 14 16 18 2 22 24 26 28 3 32 34 36 Contact: nvsrk@suven.com, jasti@suven.com 13 of 14
CSF and Brain Tissue Pharmacokinetic i. CSF concentrations of Raclopride Raclopride Concentration in CSF (ng/ml) 18 15 12 9 6 3 Raclopride - 3 mg/kg, s.c Group size: n=5/ time point Test compound: Raclopride 5. mg/kg, i.p. 15 3 45 6 75 9 ii. CSF concentrations of Carbamazepine Carbamazepine Concentrations in CSF (ng/ml) 5 4 3 2 1 Carbamazepine - 4 mg/kg, i.v Group size: n=5/ time point Test compound: Carabamazepine 4. mg/kg, i.v. 15 3 45 6 75 9 Contact: nvsrk@suven.com, jasti@suven.com 14 of 14